I travelled to the United Kingdom to help with fieldwork coordinated by Dave Lowry’s research group at Royal Holloway University of London (RHUL) in November 2017. This trip was part of a knowledge exchange between our lab and Dave Lowry (with whom our lab has previously partnered) that involved a member of each respective group joining each other’s methane measurement campaigns. We completed two days of extensive mobile measurement surveys in several different areas of the UK, all of which offered more varied scenery than that of my most recent Canadian fieldwork in Lloydminster, AB (a plus)!
Day one was spent sampling in a coal mine and around several landfills in Wales. Collected data was used for a student’s senior project, and we were able to have full site-access to the open cut anthracite mine. While at the mine, we drove down in the pit in a Land Rover to continuously measure methane using a portable LGR analyzer. We also periodically took bag samples in areas of high methane concentrations for isotopic analysis, which was done back in Lowry’s lab after the campaigns. The pit is 150 – 200 metres deep and the coal seams, which we were able to see up close, range from a few centimetres to over a metre in thickness. The mine plans to close in 2018, with remediation immediately following. The rest of the day involved scoping out smelly landfills, which was not quite as exciting as touring around a mine in a Land Rover, but still interesting none the less.
Day two consisted of continuous measurement surveys along the North Sea coast, where our main target was large onshore natural gas terminals and compressor stations. We did not have site access to these facilities, so we measured around the perimeters of them and tried to get downwind of any observed plumes.We also took several bag samples during these surveys for isotopic analysis, which made the space in the car very limited by the end of the day!
The next two days were spent in the lab back at RHUL analyzing the bag samples that were collected atsites of interest. Lowry’s lab was equipped with a high-precision, automated mass spectrometer, which was really cool to see in action. While waiting for samples to run, I also explored around the university, which was the most beautiful campus I have ever seen (sorry StFX)!
During this trip, I also represented the Flux Lab at the Industrial Methane Measurement Conference (IMMC), which was held in Antwerp, Belgium. The 2-day conference consisted of several interesting presentations on current methane measurement technologies and challenges in Europe and abroad.
This trip was my first time outside North America, and I was able to take in 3 countries in a short time; I think it goes without saying that this was a field experience I will never forget!
Many thanks to Dave Risk and Dave Lowry for the amazing opportunity.
Wind measurements are an important part of gas leak plume detection, which we do by truck. I’ve been working with ANSYS Fluent software and anemometer measurements from the mobile survey trucks to investigate vehicle-based wind measurements. My MSc. project is a field- simulation study comparing experimental field measurements with CFD simulations, to explain how anemometer placement and the vehicle’s external flow field,affect measurement accuracy of vehicle-mounted anemometers.
Along with Nayani Jensen, I conducted field tests in Saskatchewan to explore the effects of anemometer placement, vehicle speed, and wind yaw angle on measured wind speed and direction. We tested five different anemometer positions on the truck, and used stationary anemometers to compare against the mobile measurements.
We found that our truck-mounted anemometer over-estimated wind speeds, particularly for low mounting positions, high vehicle speeds, and large side winds (> 40% of vehicle speed). This indicated that corrections are needed for vehicle speed and wind yaw angle.
Back at the lab, we used a Toyota Tacoma CAD model to create Computational Fluid Dynamic (CFD) simulations using ANSYS Fluent, to study the flow field around our truck as a function of speed, yaw angle, and anemometer placements. We replicated the conditions under which field tests were conducted, but ANSYS Fluent also allowed us to explore a much wider range of conditions.
Our simulations agreed very closely with field measurements. We are working with the results from the CFD, and field components of this study, to improve our truck-based wind measurements by calibrating anemometer measurements for anemometer placement, vehicle speed, and wind yaw angle.
Measuring wind from trucks isn’t much different than measuring wind from bikes (see this blog post) or from other vessels in motion like boats. Modeling wind fields with CFD has proven a good substitute for field work in these applications.
The rock room has been a space of design and construction for many CO2 soil profilers for arctic field sites, and this summer was no exception. Jack and I created an automated soil gas sampler, for the measurement of methane and CO2 from a series of soil depth chambers in northern Norway. The system included a one-metre long, encased, open path methane analyzer that consecutively received samples from the soil depth chambers. The methane analyzer was not at our disposal during system construction, so a surrogate analyzer was created in the lab using a sealed compost bin equipped with a CO2 probe to mimic the 9L analyzer. It proved to be a great addition to the lab!
Late June Jack and I departed on a three-week journey to the Arctic. The first leg of our trip took us through Iceland to Bergen, where we had four days to work with the methane analyzer and get accustomed to the short nights before experiencing the midnight sun at 69oN. Then the whole team flew to Finnmark, the northernmost county of mainland Norway. We landed in Alta and drove a scenic three hours inland to the small town of Karasjok; the town campground was home base during our stay.
The field site is located at a mire near Iskoras, a 30 minute drive from town and a 3 km walk from the road. The site was selected for its spatial representation of the stages of permafrost degradation. There are four transects throughout the mire, each with four subsites equipped with soil chambers at depth, temperature and moisture sensors, and open top chambers.
During the July visit, another team installed an eddy covariance tower that stayed for the duration of the summer. During the July visit, another team installed an eddy covariance tower that stayed for the duration of the summer. It was a busy, challenging and enjoyable 10 days in the field that entailed many hours armpit-deep in wet soil installing chambers and created an appreciation of the midnight sun’s convenience. We enjoyed frequent chocolate breaks, unique lunches like pickled mackerel on rye, and brown cheese. Quickly, we learned not to stand too still or the mosquitoes would have a feast!
When I returned in September the berries were plentiful, the midnight sun no longer shone, and the flies were still hungry. More soil chambers were installed; 48 depth chambers were spread throughout the four transects and six surface FD chambers, relocated from Svalbard, were installed at the automatic transect. The last day in the field was spent collecting gas samples, and prepping the equipment and site for the fast approaching winter.
Many thanks to Dr. Hanna Lee, Dr. Casper Christiansen and Dr. Dave Risk for their guidance, expertise, and providing the opportunity to expand my field and technical experience throughout the development of this project.
By Renee McDonald
While pursuing my Master’s degree at St.F.X., I am working with Owen Sherwood and Dalhousie University to determine the source and the concentrations of dissolved methane in groundwater in Nova Scotia, as part of the Gas Seepage Project (GaSP). We are investigating areas that have drilled groundwater wells in close proximity to abandoned coal mines.
My undergraduate research project with Dave Risk combined my Aquatic Resources and Earth Sciences backgrounds; the project assessed methane gas in groundwater in the Stellarton region, and built upon a study by the Nova Scotia Department of Natural Resources that observed higher concentrations of methane gas compared to the rest of the province. The current GaSP campaign is a natural fit with my interests and an excellent opportunity to continue research on methane in groundwater in Nova Scotia!
My present research with Owen will generate baseline data for levels of groundwater methane in locations associated with hydrocarbon developments in Nova Scotia. Methane gas is not considered toxic to human health, but it poses explosive hazards in high concentrations as it is extremely flammable and it is the most potent greenhouse gas.
We are tracing isotopic signatures, which are like “gas fingerprints” that will help us determine the source of mystery methane. The isotopic signatures will identify whether the methane has a thermogenic, biogenic or mixed source of origin. This data will help us assess and monitor water quality in target areas, which is influential on potential future developments.
When we were out in the field certain sites had characteristics associated with methane gas and coal formations. We observed water that was either bubbly, black in colour, or had the lovely scent of rotten eggs! This gave us a good scent that methane gas was in the air…and the groundwater! We even had a Global News crew join us in the field for media coverage where they witnessed that research takes teamwork, time, patience, and getting a little dirty, which their journalist, Ross Lord, experienced first hand by dog paw.
P.S. Ross, I hope that the mud stains on your pants from the homeowner’s dog during filming came out. I guess the dog wanted to share the spotlight!
By Kim Taylor
Typically, FluxLab mobile surveys involve driving around oil and gas developments looking for fugitive emissions with a truck full of gas analysers. When I started work in the lab in January, Dave asked me to take the same mobile survey techniques that the lab has been refining over the years, and apply them to a totally different environment. After a few weeks mulling this over, I decided to see what I could find out about methane emissions in cities!
We started off with a test run in Toronto this summer. Even though it’s a bit far from Antigonish, Toronto made sense since there has already been a lot of air quality research done there, and because Debra Wunch and Greg Evans, two researchers at the University of Toronto, agreed to collaborate with us. So in late July, Susan and I packed up the truck and headed off to the big city. After a few days driving (during which we got to explore the regional changes in methane between Antigonish and Toronto) we arrived downtown and were ready to get started.
The first thing to do was to get Wunch and Evan’s analysers set up in the truck along with our own. Debra Wunch’s group has been exploring methane emissions in the city by bike, towing their gas analyser along in a trailer. This meant that it was already wrapped in a small self-contained package, and it was no trouble to pop the wheels off the trailer and move the whole thing into the truck bed. The most time-consuming part was attaching their weather station to the roof of the truck which required drilling a few holes in the support beams we already have up there (shhhhh!). Both the Wunch analyser and our own measure methane, carbon dioxide, and water; ours can additionally detect ethane and methane isotopes and theirs measures carbon monoxide. The combination of the two analysers gave us a very useful suite of analytes that should extract distinctive source signatures from different types of emissions. To top it off, Greg Evans added some portable instruments for measuring particle size and black carbon which rode in the cab with us with their sampling tubing stuck out the window.
We planned out three different routes around the city (see map) targeting different types of known methane emitters, and we wanted to cover each of these three times to get a sense of how variable these emissions are.
Over the 9 days of the campaign, we managed to target 50 or so pieces of infrastructure in triplicate, including power plants, wastewater treatment plants, and different kinds of manufacturing facilities. We decided to first drive each of the routes at night, since the trapping of emissions under a low night time boundary layer might increase concentrations and allow us to sniff out some of the weaker emitters. This meant starting surveys at 9 pm and sometimes finishing after 4 am! These night time drives were full of interesting emissions and the overall stable concentrations made it easy to see some very high enhancements above background values. As cool as it was to explore new areas while the city was totally asleep, the daytime surveys were much more pleasant. When we saw big emissions during daytime surveys, we would stop and see if we could identify the specific source of the methane, scanning the various elements of the infrastructure using a Forward Looking InfraRed camera (see left picture).
In general, the highest methane emissions we saw came from parks built on top of old landfills. This was especially the case at night when low winds and a shallow mixed layer let concentrations really build up. A few times we saw some mystery methane: sudden high concentrations in areas where we hadn’t flagged any piece of infrastructure as a likely source. This would lead to a bit of detective work as we drove zigzag around the signal, trying to figure out where it was coming from. One of these mystery spikes was the highest of any we saw, and after a bit of searching, we wound up here:
It seems like this captured patch of sludge down on the lakeshore was a stronger emitter than any of the pieces of infrastructure that we had targeted! This was quite surprising, but we’d have to do a bit more investigating to confirm it, and there’s a lot more work to be done to put this into the context of overall emission volumes in the city.
On the whole, we saw a whole lot of really interesting emission signals from different types of sources, and now it’s on to crunching through the data so that we have a better overall picture of sources in the city as we plan out our next run!
By Alex Tevlin